A crystal device such as a crystal oscillator and a crystal resonator is small and lightweight, and hence, it is used as a reference source of frequency and time in a portable electronic device, for example, a cell phone. As one such a crystal device, there is a crystal resonator in which a crystal vibrating blank is mounted on an upper surface of a base made of ceramic, a metal cover is placed on the base, and a crystal blank is hermetically sealed therebetween by seam welding. Such a crystal resonator includes one in which a pillow in a railroad sleeper shape is formed on the upper surface of the base separately before hermetic sealing to prevent frequency fluctuation and damage due to a drop impact.
Moreover, as shown in Patent Document 1, there is a piezoelectric device in which a base, a framed crystal vibrating blank, and a lid are made of the same material, for example, a crystal plate, and a buffer protrusion is respectively formed on a rear surface of the lid and an upper surface of the base, to prevent a large deflection of a crystal blank at the time of a drop impact, thereby preventing damage due to a collision.